Number one singles on the US charts for Kallen are "Bésame Mucho" (1944), "It's Been a Long, Long Time" (1945), and "Little Things Mean a Lot" (1954). By the middle of 1955, for apparent psychological reasons she lost the ability to sing in front of a live audience, but continued recording in the studio. Kallen retired altogether in the early 1960s. When an impersonator Genevieve Agostinello died in 1978, Kallen's death was erroneously reported. Outliving that premature report by 37 years, she died at the start of 2016 in Mexico.